To grow apples, we need bees. Apple growers depend on the humble honey bee to pollinate their crops, but there’s a delicate balance between hives, flowers and fruit.
Bees fertilize apples by flying from flower to flower, feeding and distributing pollen. If bees don’t pollinate enough flowers, growers are left with a miniscule crop, but too many bee visits bring the added cost of thinning, or removing small, undeveloped fruit.
“The problem for growers is that the more you pollinate, the more you have to thin,” said Vincent Jones, Washington State University entomology professor and director of the WSU Tree Fruit Decision Aid System. “Otherwise, you get tiny apples that can’t be sold.”
Throw in the vagaries of weather, climate and changing apple varieties, and it’s more challenging than ever for growers to achieve perfect pollination.
Now, scientists at WSU are evening the odds. In a three-year, $303,000 project funded by the Washington Tree Fruit Research Commission, a team led by Jones is building a precision pollination model and decision support tool to help growers efficiently pollinate their orchards.
Being tested now by Northwest growers, the new model will help Washington’s $2.4 billion apple industry be more competitive and sustainable, ultimately ensuring the supply of fruit we love.
“We’re helping growers determine precisely when they need the bees,” Jones said. “They’ll be able to get the right number of hives in place ahead of time, and then pull them out before too many flowers have been pollinated.”
His model incorporates many variables, from honeybee foraging patterns to sun, rain, wind and cloud cover and the flower behavior of the latest apple varieties.
Getting the full picture
Growers thin blossoms or fruit by chemical means, mechanically, or by hand. That can get expensive—upwards of $1,000 per acre by hand—prohibitively so for large orchards.
Jones and his colleagues designed the new model to help growers see when blossoming will occur and predict the quality of bee foraging in their local area. It will help growers decide when to leave the hives in their orchards a bit longer to ensure a good crop, or take them out to cut down on thinning, reducing fuel consumption and use of chemical sprays.
Working at WSU experimental stations, and alongside growers in Washington orchards, team members are collecting data on bee activity, blossom timing, and fruit set—the process in which flowers become fruit and mature fruit size is determined.
That includes data on modern apple varieties, including WA38, the Cosmic Crisp apple, which is being planted by the millions.
Researchers are also studying how climate change may affect timing and quality of pollination.
“Twenty years from now, there’s a strong possibility that our blooming period will be as much as six weeks early,” Jones said. “That has consequences for bee foraging. Growers may need longer pollination time and more hives.”
Part of WSU’s Decision Aid System
When finished in 2020, the model will be part of WSU’s Decision Aid System (https://decisionaid.systems/), or DAS, an important tool used by growers in the U.S. and Canada. As it is finished and validated, the model will join others on honeybee foraging and flowering times, already available on DAS for several cultivars.
“From planting and pollination to disease control and harvest, fruit growers have to make a lot of decisions that can affect everything down the line,” said Jones. “With DAS and new models like this one, we’re trying to give them a framework to make the best decisions for their orchards.”
While apples are the main focus of the new model, researchers are adding data for cherries and pears, and it could be applied to nearly any pollinated crop.
“It’s a lot of information to bring together,” Jones said. “But it’s solving a big problem for growers. It brings it all together in a tool they can use to make their orchards and businesses better.”
- Contact: Vincent Jones, Professor, Department of Entomology, 509-663-8181, vpjones@wsu.edu